I must be an idiot, but for the life of me I can't figure out how to create/save a project folder. I'm trying to do something similar to TextMate, where a parent folder is saved as a project I can then open to edit all files inside. In Sublime I open a folder, save a .sublime-project file, then double-click on the saved file. All I get is the markup of the .sublime-project file itself (not exactly helpful).

So then I tried the "Add Folder to Project" action. Did that, saved, double-clicked, blasted .sublime-project file view again with no folder linked.

What am I doing wrong? Can't find anything in the documentation that explains how this is accomplished.

Sublime remembers the latest projects you've saved, so to switch between them you use the Prompt to Select Project (Ctrl+Alt+P).

.sublime-project files are not registered as any specific file type with your OS, so they open as plain files in sublime. Only .sublime-package files do have an associated command as far as Sublime is concerned.